As part of its program to evaluate new treatments, the section is studying the clinical pharmacology of drug of abuse and potential treatment medications. This also entails the development of laboratory screening procedures in which a potential treatment medication can be tested for its ability to block the rewarding effects of a drug of abuse. Desirable properties for such a screen include convenience and safety. For example, low doses of orally administered cocaine might have a relatively benign profile of cardiovascular effects while remaining discriminable and euphorogenic. In an NIDA/IRP study designed to examine this, drug-abusing volunteers were administered 50 mg oral cocaine or placebo, then given a behavioral-testing procedure that permitted precise measurement of the time course of drug effects within each of 50 two-hour sessions. Oral cocaines effects began at a longer latency than has been reported for other routes and had a longer duration. Six out of seven participants acquired the discrimination (though this typically required 15 to 30 sessions). In most participants, oral cocaine produced increases in ratings of liking, alertness, and good effects, and in motor performance. Nonetheless, for most participants, peak heart rate and blood pressure remained within the range seen with placebo. (Additional testing with one participant suggested that oral cocaine was discriminable and liked at 25 mg and possibly 12.5 mg.) There were some intriguing dissociations between oral cocaines discriminability and its identifiability as a stimulant. Overall, however, the results support the discriminability and possible research utility of oral cocaine. (Epstein DH, Silverman K, Henningfield JE, and Preston KL. Behavioural Pharmacology, in press.) - human behavioral pharmacology, substance abuse, substance abuse treatment, drug discrimination, cocaine - Human Subjects